Modified locust bean gum, solution thereof, and process for making a locust bean gum solution



Patented July 7, 1 953 7 MODIFIED LOCUST BEANYGUM, SOLUTION THEREORAND \PROCESS'FORMAKING A -LOCUST BEAN-.GUM soL T on- 1 ,Nat' r sc Whi mains an ,FE tiik .i,.stehe 1' Fprest Hi lls lfL'Yg; assignors to'QS tein, Hall &

Company;' Inc., New YorkQN X, a corporation he pawl-lg; j riginal agitate. December 16,

1 94 8, S crial,No. 65,718. Divided and; this application. June 26, 1 951, serial No 233,604,

'10 Claims";

The present invention relates to locustbea'n gum, modified to render it readily dispersible' in water, to a method of dispersing and gelatinizing locust bean gum solution thereof.

This application is a division f app1ication Serial No. 65,718, filed DecemberlS, 1948., i

It'has been k'nownfor sometime that locust bean-gum powder or flour, which is obtained from i, the fleshy seeds in the fruit of the locust or carob tree (Cemtonia silz'qwa), a perenniallegume native to the Mediterranean region, has desirable adhesive and deflocculating properties which make it useful in the preparation of felted sheet material such aspaper. It has, also been known,

however, that it is extremely difiicultrto disperse locust bean gum uniformly in water so that its ability to deflocculate'fibers suspended in an in water, and to an aqueous w aration of an aqueous locust bean gum solution must frequentlybe cleaned to remove a thick and gummy scum formed on all parts that come in contact with the gum. The great amount of patience required to obtain a dispersion of the gum and the extra time and equipment made.

necessary thereby are apparently responsiblefor the limited use that has heretofore been made of locust bean gum in spite of its otherwise promising characteristics.

It has now been found that locust bean gum can be readily dispersed in water in the presence of a sodium borate such as, for example-sodium tetra borate (borax) and sodium meta-borate, and an aldehyde selected from the group consisting of glyoxal and pyruvic aldehyde or an acidreacting compound selected from the group con sisting of ammonium chloride, citric acid, boric acid and aluminum sulfate. are obtained when the borate and the aldehyde trons, of borate and aldehyde or acid-reacting compound, is'di'spersible without difliculty in cold water. When the dispersion is cooked, e. gqby raisin'g'itstemperature to about 200 F., the 10- cust bean gumfopens or swells to form a clear, yiscous solution that is free of lumps and does "not require straining before. it is used as an additiveto an aqueous suspension of fibrous material 's'uchas, for examplega .stock suspension from which paper is made. It forms no scum, leaves the mixing equipment cleanand obviates the necessity of using special equipment such as strainers and injectors in its preparation. The mixture'need not be added slowly, as is necessary with straight locustbean gum, but can be dumped directly into cold water without increasing its liability to form lumps.

fThe proportions of the various components nlayvary widely, depending on the results desired. Generally no difficulty is experienced in dispersing mixtures'fcontaining up to about 90% b'y' 'weight oflocust bean gum powder. As the proportion of locust bean gum powder increases from 90% and approaches 100%, the difficulty ,of dispersing the mixture in water increases by -degrees but mixtures containing as high as 96% locust bean gumpowder can, if added gradually and stirred "vigorously, be dispersed without forming lumps either. before or after cooking.

It is surprising also that, weight for weight, themixture has, within the limits of measurable error, beneficial effects on the final felted sheet material that are superior to those obtained with I straight locust bean gum so long as the proportion of locust bean gum in' the mixture is not substantially below about Thus, forexample, it has been found that the bursting, tearing and folding strengths of paper produced by addition to the suspended stock at a rate of five pounds of a mixture consisting of 85% locust bean gum, 10% borate and 5% aldehyde or acid-reacting compoundwin'dispersed form per ton of paper stock, based on the dry weight, are superior to those produced by the addition of straight locust Optimum results or acid-reacting compound are thoroughly admixed, in the dry state, with locust bean gum powder prior tothe addition thereof to water. Itfis surprising that a mixture of locust bean gum powderfeven with relatively small properbean gum at the same rate.

In viewof the foregoing considerations, the

proportion of locust bean gum powder should generally range between about 50 and 96%, the

lower limit being determined by the efficacy of the mixture when compared with that of straight locust bean gum andthe upper limit being determined by the practicability with which it can readily be dispersed in water without forming lumps? The range of proportions that is preferred is from about 'to 93% and optimum results, from the standpoint of ease of dispersion, uniformity of appearance and efficacy in paper making processes, have beenobtained with mixtures containing about 85 to 90% by weight of The mixture of this invention has excellent storage properties, bagged samples of the powder having undergone no perceptible change in either appearance or dispersibility even after storage for Barium Peroxide Sodium Perborate Dowlcide A locust bean s m p w several months. 'It can be readily dispersed by The relative proportions of borate and aldehyde dumping it into cold water and cooked by heating acid-reacting comp u ay also Vary and to an elevated temperature of the order of about depend upon the consistency and characteristics 165 F. to-2l2 F., preferably about 200 F. In desired in the aqueous solution formed when the practice, it has been found advantageous, e. g., miXtul'o is added o Water d o e he where it is desired to form a solution containing bcrate tends to impart o th cooked solutionv a .99% by weight of water,'to add the mixture to heavy y, high film Strength n i i eSS- half the required amount of water at tap or room The aldehyde 0 i -r acting compound reduces temperaturestir and heat it to about 200 F. and the ropiness of the cooked solution and imparts then add the, remainder of the water. a I nsr n y ch r er h I h The solution formed by this method is transy been found desirable to j t' ti parent,v viscous and stringy at room temperature p p i f locust e r t and d and is sufiiciently free flowing at temperatures of hyde r a a ti mpou s tha t e s uthe order of 160 to 185 F. to be pumped Without tion or dispersion thereof in water will have a difliculty through 1" i 1011 b w n 3 and l n r r y at about -0 To further illustrate the utility of the mixture The rotio of bolalloto aldehyde a of this invention and of the aqueous solution reacting compound y Vary from about 111 to thereof, and to compare its efficacy in the pro- 311 and is preferably about The proportions duction of paper, the following examples are inby weight in the mixture are desirably from about l d d, 2% to about 35%, preferably from about 5% to 1 about 10%, of .borate and from'about 1% to about 7 v V 20%, preferably from about 2% to about 6%, al- Foul batches loc t boon u aX a d dehyde or acid-reacting compound. ox Corresponding o FormulaoNos- 1, 3 I It is to be understood that other materials, and 4 of Table 1, w e made up on a laboratory compatible with the three essential ingredients, scale. A 17% aq s So ut o of each batch was may be added. Thus, for example, starch may be o m by d p in on p rt y wei ht f he added if it is desired to reduce the proportion of dry mixture in about 5 0 parts by W ht of Water, locust bean gum below bo t, 30%, small cooking the resulting dispersion to 200 F. and amounts of oxidizing agents, such as barium pethen adding sullicient additional water to brin roxide and sodium perborate may be added to 3 the concentration of solids down to 1% y e thin out the solution prepared when the com- The temperature of these solutions was main.- bination is dissolved in water. 7 mined at about 0 H The mixture may be formed simply by A 1% solution of locust bean gum alone was thoroughly mixing the components together in prepared in a similar manner, f the dry state. Where glyoxal, which is normally go A number of paper making runs on a laborain the liquid state, forms one of the components, tory scale, corresponding to the number of soluit is sprayed on one or more of the, other comtions prepared, were then made. In each run, ponents prior to or duringthe dry mixing operaone of the prepared solutions was added to the tion. furnish at a rate 01*"1'0 lbs., based on the dry Without intending to limit in any way the scope weight, of solution to a ton. of furnish, likewise of the present invention, a number of typical based on the dry weight. j i formulae arelisted in the tables below, the nu- Two sheets each having a weight of 2.8 grams merals therein referring to percentages by weight. were selected from each run to eliminate test Table 1 FormulaNo 1 2 3 4 5 6 7 s 9 10 11 Locust Bean Gum s5 s7 90 90 s5 as so so so I 84 Borax 10 7 5 s 10 10 12 20 26.5 33.3 11 Glyoxal 5 6 5 4 5 5 5' 5 Pyruvic Aldehyde 2 Ammonium Chloride l. 5 8.4 11.7 3

Table 2 Formula No 12 1a 14 15 16 17 18 19' 20 21 Locust Bean Gum 85 84 96 Powdered Potato Starch orax l0 l0 2 Sodium Metaborate Glyoxa1 5 1 Citric Acid. Boric Acid Aluminum Sulfate which is sodium orthophenylphenate.

errors due to vari t ons in the ,weight of the .sheets produced and each sheet selected was subjected to ten mullen tests. The averages of the twenty mullen tests in each run are tabulated below:

Formula No.

4 Locust Been Gum Alone." 30. 85

EXAMPLE 2 Dry mixtures corresponding to Formulae Nos. '7, 8, 9, 10, 11, 13, 14, 16, 18, 19 and 20 were made up, on a laboratory scale, into 1% aqueous solutions by dispersing one'part by'weight of each ing a locust bean gum containing solution to the furnish and the modified sheets were made by adding. one of the prepared solutions at a rate of 10 lbs., based on the dry weight, of solution to a ton of furnish, likewise based on the dry weight.

Two blank sheets and two modified sheets each having a Weight of 2.8 grams were selected from each run to eliminate test errors due to variations in the weight of the sheets produced and each sheet selected was subjected to ten mullen tests. The averages of the twenty mullen tests conducted on each set of two sheets are tabulated below:

Blank Sheets Formula No. Sheets It is to be understood that innumerable modifications will readily occur to those skilled in the art upon reading this description. All such modifications are intended to be included within the scope of the present invention as defined in the appended claims.

We claim:

1. A mixture comprisin from about 50% to about 96% by weight of locust bean gum powder, from about 2% to about 35% by weight of a sodium borate and from about 1% to about 20% by weight of citric acid, the relative proportions of borate to acid ranging from about 1: 1 to 3: 1.

'2. A mixture comprising from about 85% to about 90% by weight of locust bean gum powder,

from about 5% to about 10% by weight of a sodium borate and from about 2% to about 6% by weight of citric acid, the relative proportions of borate to acid being about 2:1.

3. An aqueous solution wherein about 50% to 96% by weight of the solute is locust bean gum, about 2% to by weight of the solute is a sodium borate and about 1% to 20% by weight of the solute is citric acid,

4. An aqueous solution wherein about 85% to 90% by weight of the solute is locust bean gum, about 5% to 10% by weight of the solute is a sodium borate and about 2% to 6% by weight of the solute is citric acid.

5. A method of preparing an aqueous solution of locust bean gum in water which comprises adding to water a mixture of locust bean gum powder, a sodium borate and citric acid, and heating it to a temperature of about 200 F.

6. A method of preparing an aqueous solution of locust bean gum in water which comprises adding to water a mixture containing to 96 parts by weight of locust bean gum powder, 2 to 35 parts by weight of a sodium borate and 1 to 20 parts by Weight of citric acid, and heating it to a temperature of about 200 F.

7. A method of preparing an aqueous solution of locust abean gum in water which comprises adding to water a mixture containing 85 to 90 parts by weight of locust bean gum powder, 5 to 10 parts by weight of a sodium borate and 2 to 6 parts by weight of citric acid, and heating it to a temperature of about 200 F.

8. A method of preparing an aqueous solution of locust bean gum which comprises dispersing locust bean gum powder in water in the presence of a sodium borate and citric acid, and heating the dispersion to a temperature of about 200 F.

9. A method of preparing an aqueous solution of locust bean gum which comprises dispersing 50 to 96 parts by weight of locust bean gum powder in water in the presence of 2 to 35 parts by weight of a sodium borate and 1 to 20 parts by weight of citric acid, and heating the dispersion to a temperature of about 200 F.

10. A method of preparing an aqueous solution of locust bean gum which comprises dispersing to parts by weight of locust bean gum powder in water in the presence of 5 to 10 parts by Weight of a sodium borate and 2 to 6 parts by weight of citric acid, and heating the dispersion to a temperature of about 200 F.

NAT FRISCH. FRANK J. SWEENEY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,106,335 Pinel Aug. 4, 1914 FOREIGN PATENTS Number Country Date 508,135 Great Britain June 27, 1939 OTHER REFERENCES Tagliani, Jour. Soc. Dyers Colourist 45 (1929), pages 344-349. 

1. A MIXTURE COMPRISING FROM ABOUT 50% TO ABOUT 96% BY WEIGHT OF LOCUST BEAN GUM POWDER, FROM ABOUT 2% TO ABOUT 35% BY WEIGHT OF A SODIUM BORATE AND FROM ABOUT 1% TO ABOUT 20% BY WEIGHT OF CITRIC ACID, THE RELATIVE PROPORTIONS OF BORATE TO ACID RANGING FROM ABOUT 1:1 TO 3:1. 